Baseline trace metals in seagrass, algae, and mollusks in a southern Tyrrhenian ecosystem (Linosa Island, Sicily).

Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas.